Binding of 4-methylumbelliferyl α-D-mannopyranoside to dimeric concanavalin A: fluorescence temperature-jump relaxation study

Clegg, Robert M.; Loontiens, Frank G.; Jovin, Thomas M.

doi:10.1021/bi00621a002

Cited by 50 publications

(28 citation statements)

References 33 publications

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“…where K 1 ϭ k 1 /k Ϫ1 and K II ϭ k 2 /k Ϫ2 are the association constants for the two steps (23,24,25), E is the enzyme, S is the ligand i.e. alanine, and ES i and ES represent the intermediate and the final external aldimine complexes, respectively.…”

Section: Discussionmentioning

confidence: 99%

Broad Substrate Stereospecificity of the Mycobacterium tuberculosis 7-Keto-8-aminopelargonic Acid Synthase

Bhor

Dev

Vasanthakumar

et al. 2006

Journal of Biological Chemistry

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Biotin is an essential enzyme cofactor required for carboxylation and transcarboxylation reactions. The absence of the biotin biosynthesis pathway in humans suggests that it can be an attractive target for the development of novel drugs against a number of pathogens. 7-Keto-8-aminopelargonic acid (KAPA) synthase (EC 2.3.1.47), the enzyme catalyzing the first committed step in the biotin biosynthesis pathway, is believed to exhibit high substrate stereospecificity. Biotin (vitamin H) is an essential cofactor required for a number of carboxylation, transcarboxylation, and decarboxylation reactions in all living organisms. Its participation in gluconeogenesis, metabolism of amino acids, and initiation of fatty acid biosynthesis makes it an indispensable entity in cellular metabolism. However, only plants and microorganisms are capable of synthesizing biotin, whereas mammals obtain it either from the diet or from the intestinal microflora (1). The biotin biosynthesis pathway has been studied in detail in microbes like Escherichia coli, Bacillus subtilis, Bacillus sphaericus, and Saccharomyces cerevisiae and in plants like Arabidopsis thaliana and Lavandula vera. With the exception of the first step, which is the synthesis of pimeloyl-CoA, the remaining four steps of the pathway (Scheme 1) are invariant in all biotin-synthesizing organisms and are carried out by four committed enzymes (2). The first of these four steps is the decarboxylative condensation of pimeloyl-CoA and L-alanine to 7-keto-8-aminopelargonic acid (KAPA) 3 catalyzed by KAPA synthase, followed by the DAPA synthase-catalyzed transfer of an amino group from S-adenosylmethionine to KAPA, forming DAPA. DAPA is then converted to dethiobiotin by the addition of CO 2 in an ATP-dependent reaction catalyzed by dethiobiotin synthetase, and finally the biotin synthase-catalyzed insertion of a sulfur atom between the reactive methyl and methylene carbon atoms adjacent to the ureido ring of dethiobiotin to generate biotin (1-3).KAPA synthase is a PLP-dependent enzyme belonging to subclass II of the aminotransferase family. Along with 5-aminolevulinate synthase, serine palmitoyltransferase, and 2-amino-3-oxobutyrate-CoA ligase, which typically catalyze the Claisen condensations between amino acids and acyl-CoA thioesters, it forms the ␣-oxoamine synthase subfamily. The similarities in the sequences of these enzymes as well as the reactions catalyzed by them indicate that they share a common catalytic mechanism (4 -6). Availability of the three-dimensional structures of these enzymes has provided a structural basis for understanding the reactions catalyzed by them (4, 7-9). The knowledge of the reaction mechanism of KAPA synthase in particular is based on studies on the Bacillus sphaericus and E. coli enzymes (7, 10 -11). It involves the displacement of lysine from the internal aldimine complex with PLP resulting in the formation of the external aldimine between PLP and L-alanine. This is followed by the abstraction of the C␣-H proton of the L-alanine external ald...

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Section: Discussionmentioning

confidence: 99%

Broad Substrate Stereospecificity of the Mycobacterium tuberculosis 7-Keto-8-aminopelargonic Acid Synthase

Bhor

Dev

Vasanthakumar

et al. 2006

Journal of Biological Chemistry

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“…The value of K a can, therefore, increase with either an enhancement in the values of k 1 or a diminution of k ÿ1 . In general, for most biologic recognition processes including enzyme-substrate, lectin-sugar interactions, etc., it is usually the reduction in the dissociation rate constants which determines the affinities of cogners (Clegg et al, 1977). In the case of PDC-109-phospholipid interaction, it is the enhanced k 1 that dictates the resultant affinities of binding.…”

Section: Discussionmentioning

confidence: 99%

Mechanism of Membrane Binding by the Bovine Seminal Plasma Protein, PDC-109: A Surface Plasmon Resonance Study

Thomas

Anbazhagan

Ramakrishnan

et al. 2003

Biophysical Journal

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PDC-109, the major protein of bovine seminal plasma, binds to sperm plasma membranes upon ejaculation and plays a crucial role in the subsequent events leading to fertilization. The binding process is mediated primarily by the specific interaction of PDC-109 with choline-containing phospholipids. In the present study the kinetics and mechanism of the interaction of PDC-109 with phospholipid membranes were investigated by the surface plasmon resonance technique. Binding of PDC-109 to different phospholipid membranes containing 20% cholesterol (wt/wt) indicated that binding occurs by a single-step mechanism. The association rate constant (k(1)) for the binding of PDC-109 to dimyristoylphosphatidylcholine (DMPC) membranes containing cholesterol was estimated to be 5.7 x 10(5) M(-1) s(-1) at 20 degrees C, while the values of k(1) estimated at the same temperature for the binding to membranes of negatively charged phospholipids such as dimyristoylphosphatidylglycerol (DMPG) and dimyristoylphosphatidic acid (DMPA) containing 20% cholesterol (wt/wt) were at least three orders of magnitude lower. The dissociation rate constant (k(-1)) for the DMPC/PDC-109 system was found to be 2.7 x 10(-2) s(-1) whereas the k(-1) values obtained with DMPG and DMPA was about three to four times higher. From the kinetic data, the association constant for the binding of PDC-109 to DMPC was estimated as 2.1 x 10(7) M(-1). The association constants for different phospholipids investigated decrease in the order: DMPC > DMPG > DMPA > DMPE. Thus the higher affinity of PDC-109 for choline phospholipids is reflected in a faster association rate constant and a slower dissociation rate constant for DMPC as compared to the other phospholipids. Binding of PDC-109 to dimyristoylphosphatidylethanolamine and dipalmitoylphosphatidylethanolamine, which are also zwitterionic, was found to be very weak, clearly indicating that the charge on the lipid headgroup is not the determining factor for the binding. Analysis of the activation parameters indicates that the interaction of PDC-109 with DMPC membranes is favored by a strong entropic contribution, whereas negative entropic contribution is primarily responsible for the rather weak interaction of this protein with DMPA and DMPG.

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“…For most enzyme-substrate interactions and also for the lectin-sugar interactions studied so far, it is the decrease in the dissociation rate constants that has been shown to be responsible for the increased binding affinities (25). In these studies on ASAImanno oligosaccharide interaction, the occurrence of both, i.e.…”

Section: Documented Inmentioning

confidence: 99%

On the Stringent Requirement of Mannosyl Substitution in Mannooligosaccharides for the Recognition by Garlic (Allium sativum) Lectin

Bachhawat

Thomas

Amutha

et al. 2001

Journal of Biological Chemistry

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The kinetics of the binding of mannooligosaccharides to the heterodimeric lectin from garlic bulbs was studied using surface plasmon resonance. The interaction of the bound lectin immobilized on the sensor chip with a selected group of high mannose oligosaccharides was monitored in real time with the change in response units. This investigation corroborates our earlier study about the special preference of garlic lectin for terminal ␣-1,2-linked mannose residues. An increase in binding propensity can be directly correlated to the addition of ␣-1,2-linked mannose to the mannooligosaccharide at its nonreducing end. Mannononase glycopeptide (Man 9 GlcNAc 2 Asn), the highest oligomer studied, exhibited the greatest binding affinity (K a ‫؍‬ 1.2 ؋ 10 6 M ؊1 at 25°C). An analysis of these data reveals that the ␣-1,2-linked terminal mannose on the ␣-1,6 arm is the critical determinant in the recognition of mannooligosaccharides by the lectin. The association (k 1 ) and dissociation rate constants (k ؊1 ) for the binding of Man 9 GlcNAc 2 Asn to Allium sativum agglutinin I are 6.1 ؋ 10 4 M ؊1 s ؊1 and 4.9 ؋ 10 ؊2 s ؊1 , respectively, at 25°C. Whereas k 1 increases progressively from Man 3 to Man 7 derivatives, and more dramatically so for Man 8 and Man 9 derivatives, k ؊1 decreases relatively much less gradually from Man 3 to Man 9 structures. An unprecedented increase in the association rate constant for interaction with Allium sativum agglutinin I with the structure of the oligosaccharide ligand constitutes a significant finding in protein-sugar recognition.The structurally and evolutionarily related monocot mannose-binding proteins comprise a superfamily of mannose-specific lectins. Amaryllidaceae, Alliaceae, Araceae, Orchidaceae, Iridaceae, and Liliaceae families have been shown to possess these bulb lectins (1). Among the unique features that set them apart from the Glc/Man/Gal-specific family of dicotyledonous legume lectins and the C-type mannose-binding animal lectins is their high degree of stereospecificity for mannose, so much so that they show no binding propensity even for its epimer, glucose, or the conformationally related analog, L-fucose. Their classification into the mannose-specific lectin family is corroborated by determination of the crystal structures of snowdrop (Galanthus nivalis) (2), daffodil (Narcissus pseudonarcissus) (3), bluebell (Scilla campanulata) (4), amaryllis (Hippeastrum hybrid) (5), and garlic (Allium sativum) lectin (6), representatives of the family of bulb lectins. Their subunits have been observed to possess a novel 3-fold symmetry having three fourstranded antiparallel ␤-sheets arranged as three sides of a triangular prism, forming a 12-stranded ␤-barrel referred to as the ␤-prism II fold. These 12 strands are positioned perpendicular to the plane of symmetry, unlike the other known all-␤-folds: ␤-prism I (e.g. Jacalin; (7)) and the ␤-trefoil (e.g. amaranthin; (8)) fold (6). The central region in the ␤-barrel is stacked with conserved hydrophobic side chains, which stabilize th...

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Binding of 4-methylumbelliferyl α-D-mannopyranoside to dimeric concanavalin A: fluorescence temperature-jump relaxation study

Cited by 50 publications

References 33 publications

Broad Substrate Stereospecificity of the Mycobacterium tuberculosis 7-Keto-8-aminopelargonic Acid Synthase

Broad Substrate Stereospecificity of the Mycobacterium tuberculosis 7-Keto-8-aminopelargonic Acid Synthase

Mechanism of Membrane Binding by the Bovine Seminal Plasma Protein, PDC-109: A Surface Plasmon Resonance Study

On the Stringent Requirement of Mannosyl Substitution in Mannooligosaccharides for the Recognition by Garlic (Allium sativum) Lectin

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